Stress and reliability analyses of ceramic femoral head of hip joint endoprosthesis, with view to local shape deviations of cone contact areas

conference paper

English

At present, implants are frequently used in clinical practice to return functionality to various parts of the human body. One big group make the implants of joints, one of the most frequently operated joints of the human body being the hip joint. At present, the problems of reliability of ceramic femoral heads for hip joint endoprosthesis are topical, as in a not negligible number of patients their destruction in vivo had taken place. Therefore stress and reliability analyses of the ceramic heads were made using computational modelling aimed at finding the causes of the head destruction. In the course of computational modelling it was stated that a pronounced influence on the stress and, hence, the reliability of the ceramic head, had the global and local unevenness of the cone contact areas of the head and the stem. Fig. 1. The stress and reliability studies made up to now have taken into consideration only the influence of model manufacturing inaccuracies, such as deviation from nominal cone shape, and non-circularity of cone contact areas, and their interactions. On the real contact areas, however, there are real manufacturing inaccuracies which can substantially differ from the model ones. That is why measurements have been made of shape deviations of cones of stems and heads, using an IMS UMPIRE measuring appliance. This paper deals with the analysis of stress in and reliability of a ceramic head, taking into consideration the measured deviations of contact areas of the head and the stem.

Hip joint endoprosthesis, production deflections, computational modelling

FUIS, V.

2003

24. 8. 2003

IFMBE

Sydney, Australia

1877040142

Medical Physics and Biomedical Engineering

Volume 4

CD

4